Thick and hearty monster cookies that are loaded with peanut butter, oats, chocolate chips and M&Ms. These big and chunky cookies are so versatile and so much fun to make!

These monster cookies have skyrocketed to the top of my all time favourite cookies list. They’re so soft and chewy, every time I make them I get pleasantly surprised with just how delicious they are. Peanut butter is such a wonderful ingredient to bake with and combining it with oats and chocolate is truly irresistible.
Cookies are so much fun to make and I have a ton of recipes and variations to share. These beloved double chocolate fudge cookies and these amazing Hobnob biscuits are already family favourites and top posts on my site.

This recipe is super easy and you can add pretty much anything to the dough. I also love that you can make them nice, big and chunky without the worry that they will spread too much.
Why you will love these cookies
- Super easy and can be made using just a regular whisk.
- Pantry staple ingredients that are interchangeable.
- Big, thick and chunky which is the best way to eat cookies.
- Loaded with flavour and texture.
- Absolutely delicious!
First off, we start with melted butter which makes the monster cookies extra chewy. Then comes the soft brown sugar. This is a must for both texture and flavour. I added a bit of white sugar too because I love the flavour and I wanted to make sure the cookies are spreading enough. We’re not making tennis balls here 😂
Next we start adding the yumminess 😄 bring on the peanut butter baby! Make sure to use chunky peanut butter. That extra crunch is soo good.
Fold in the dry ingredients which includes a hefty dose of oats then toss in the goodies. Lots of M&Ms and chocolate chips.
Just look how pretty!

When you come to make the cookies, you’re going to take a 1/4 cup sized scoop of dough. Yup nice big and thick cookies! With this amount of dough, you can easily make 12 large cookies.
You can either leave them as balls for extra thick cookies or flatten them slightly. I suggest making one of each first to see how they bake then you can decide how to bake the rest.
Don’t forget to push some extra M&Ms and chocolate chips on top of each cookie.


Bake em, stack em, get a tall glass of milk and start devouring my friends.

Substitutions
- I love using chunky peanut butter for the extra peanuty-ness but you can defiinately use creamy peanut butter too.
- I actually prefer quick cooking oats in this recipe but you can also use old fashioned or rolled oats instead.
- Chocolate chips are a classic addition but feel free to switch between dark chocolate, white chocolate, chocolate chunks or even nuts.
- You can switch it up and use other candies in place of the M&Ms such as Smarties or Reeses Pieces.
- I have made these cookies straight away without chilling the dough but I highly recommend letting putting the dough in the fridge for at least 2 hours. The taste and texture is incomparable when you let the dough chill overnight.
More cookie recipes:
- Red velvet cookies.
- Gingerbread cookies.
- Nutella chocolate cookies.
- Snickerdoodles.
- Favourite chocolate chip cookies.
- Double chocolate cookies.
Remember to tag me with all your dutch baker bakes @dutchbakerblog on Instagram, Facebook or Twitter.

M&Ms and chocolate chips are always a great addition in cookies, these cookies look incredible and would love to try them out!
Thank you!! 😊 they really are a wonderful addition to anything 😃😄
I am speechless my friend….I have no words. I think I must have gained a couple kilo’s just reading about the absolute deliciousness of these cookies. Again, I probably will have to make a double batch, as trust me a good amount of cookie dough is going to be devoured and that is not even talking about the M&M’s, and chocolate bits……
OMW !!!!! xxx
Hahaha yep a double batch is definitely recommended in this case! 😊 I totally understand why they’re called monster cookies, they’re just loaded with goodness!! 😋😋 thanks so much for stopping by hun 💜💛
Yummy cookies! Love the chunky peanut butter in it😍😋
Thank you! The chunky peanut nutter is the best! <3
These looks delicious. I’m a sucker for M&M cookies.
Thank you!! Yeah M&Ms really do make everything better don’t they 😊😊
I love Monster Cookies and these look so good! I usuallly think of making them this time of year for some reason! 🙂
Thank you so much Nancy 🥰 yep cookies are always a favourite this time of year 💜
Super moist and fudgy in the middle yet with the perfect crunch on the outside. An all around epic monster cookie!
Thank you so much 🥰